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(i litre), connected with a long- condenser and dropping funnel
as shown in l<'ig. Si.

'Hie methyl iodide and 50 c.c. of dry ether are mixed in a
separate vessel and 20 c.c.
of this mixture poured on
to the magnesium. In a few
seconds a vigorous action
usually sets in or if it is de-
layed may be started by
adding a crystal of iodine.
When the first reaction has
subsided, 70 c.c. of dry ether
are added, and the remainder
of the alkyl iodide and ether
mixture run in drop by drop
from the tap-funnel. The
contents of the Mask arc
then boiled on the water-bath for half an hour when (if there
has been no loss of alkyl iodide) the magnesium completely dis-

Fic.  8r

The flask is now disconnected and whilst it is kept cool in ice-
water the ben/aldehyde mixed with an equal volume of dry ether
is dropped in from a tap-funnel with constant shaking. The
white solid magnesium compound separates and is left over-
night. ^

The contents of the flask are cooled under the tap whilst water
and just sufficient hydrochloric acid to dissolve the magnesia
are added, the acid being cautiously dropped in from a tap-
funnel. The aqueous layer is removed in a separating funnel
and the ether washed first with sodium bicarbonate solution,
then with sodium bisulphite (to remove free iodine) and again
with sodium bicarbonate.